1. Field of the Invention
The present invention relates to an improved method for the preparation of improved tire liners which utilize a strip of high temperature and pressure (HPT) molded and vulcanized rubber or another tread supporting material which allows low temperature and pressure (LPT) vulcanizable rubber to flow to and bond to the strip. In particular the present invention relates to a method wherein during molding and vulcanization LPT vulcanizable rubber is caused to flow to the short sides of the HPT strip to form highly flexible and elastic wings.
2. Prior Art
Tire liners which fit inside a pneumatic tire casing adjacent to the tread to provide puncture protection are well known to those skilled in the art. The present invention relates to a type of tire liner which relies upon the materials of construction of the liner in order to resist penetration of objects through the liner to the inside of a tire, particularly to an inner tube which if punctured causes a flat tire. U.S. Pat. No. 4,197,893 to O'Coin describes a foamed tire liner. The liner also acts to stabilize the tread area of the tire.
In prior application Ser. No. 139,430, filed Apr. 11, 1980 now U.S. Pat. No. 4,263,074, which is based upon application Ser. No. 59,720, filed June 25, 1979, the prior art in relation to tire liners is described in great detail. This prior art does not describe a tire liner made from HPT and LPT strips of rubber. U.S. Pat. Nos. 521,006; 1,371,097; 1,384,243; 1,460,794; 1,168,709; 1,176,424; 1,181,065; and 2,781,074 show other liners.
The present invention relates to an improvement in the method for the fabrication of tire liners using an HPT strip as described in the preceding applications Ser. Nos. 51,720 and 139,430 as well as using other similar tread supporting materials. In the construction of tire liners according to the preferred method of the preceding applications, strips of LPT vulcanizable rubber were bonded at least along the short sides of a HPT core strip as wings and the resulting composite was then molded and vulcanized to form the tire liner. This method produces a very satisfactory tire liner; however, considerable effort is needed to provide the LPT strips on the short sides of the HPT strip. Cutting and shaping of LPT rubber is disclosed in order to produce the wings.